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Re: How to restrict the possible values of a class?

From: Tom Van Eetvelde <tom.van_eetvelde@alcatel.be>
Date: Tue, 27 Jun 2000 15:22:39 +0200
Message-ID: <3958AA9F.2E730214@alcatel.be>
To: Pierre-Antoine CHAMPIN <champin@bat710.univ-lyon1.fr>
CC: "McBride, Brian" <bwm@hplb.hpl.hp.com>, www-rdf-interest@w3.org
Hello Pierre-Antoine,

Your answer confuses me. I agree that DayRange should not be a class, but an instance. Then you state:
"declare Range as a subclass of class...". Did you mean 'DayRange' or really 'Range'?

In the latter case I don't see what you are driving at. Some RDF would be helpful.

In the first case, I would then declare DayRange as an instance of Range and with the property
sublcassOf. However, subclassof may only be used on classes, not on instances. So this doesn't result in
a solution.

Could you clarify a bit (possibly with some RDF)?

Thanks,

Tom.

Pierre-Antoine CHAMPIN wrote:

> Tom Van Eetvelde wrote:
> >
> > Hello Brian,
> >
> > That only solves half the problem as I still cannot state that the subclass DayRange only runs from
> > 1 to 31. Try to write it down in RDF, you'll see that it doesn't work. Could this be a flaw in the
> > RDF schema? In OO programming, one can make subclasses of a base class and in the subclass restrict
> > properties of the base class to certain values. This is exactly what I am trying to do here, but it
> > seems that RDF doesn't support this kind of construction.
>
> It does not seem right to me that DayRange be a subclass of Range :
> typically, Range is a class and DayRange is the instance,
> but DayRange may ALSO be a class (in which case Range is a metaclass)
>
> This is absolutely possible in RDF,
> you just have to declare that Range is a subclass of class
> (and that is IS also a class, as you did - both things are different !)
>
>   Pierre-Antoine
>
> --- Quid quid Latine dictum sit, altum viditur
>     Whatever is said in Latin sounds important.

Received on Tuesday, 27 June 2000 09:23:42 GMT

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